Composition and function of solar panel

At present, crystalline silicon materials (including polycrystalline silicon and monocrystalline silicon) are the most important photovoltaic materials, with a market share of more than 90%, and will remain the mainstream materials of solar cells for a long time to come.

The production technology of polysilicon materials has long been in the hands of 10 factories of 7 companies in 3 countries, including the United States, Japan and Germany, forming a situation of technology blockade and market monopoly.

The demand for polysilicon mainly comes from semiconductors and solar cells. According to different purity requirements, it can be divided into electronic grade and solar grade. Among them, electronic grade polysilicon accounts for about 55%, and solar grade polysilicon accounts for 45%

With the rapid development of photovoltaic industry, the growth rate of the demand for polysilicon from solar cells is higher than that of semiconductor polysilicon. It is estimated that the demand for solar polysilicon will exceed that of electronic grade polysilicon by 2008.

In 1994, the total output of solar cells in the world was only 69MW, while in 2004 it was close to 1200MW, increasing 17 times in just 10 years. Experts predict that the solar photovoltaic industry will surpass nuclear power as one of the most important basic energy sources in the first half of the 21st century.

Solar panel composition and functions of each part:

(1) Toughened glass: it is used to protect the main body of power generation (such as battery chip), and the selection of light transmission is required:

1. The light transmittance must be high (generally more than 91%); 2. Ultra white steel treatment.

(2) EVA: It is used to bond and fix the toughened glass and power generation main body (battery chip). The quality of transparent EVA material directly affects the service life of the module. EVA exposed to the air is prone to aging and yellowing, which affects the light transmittance of the module, thus affecting the power generation quality of the module. In addition to the quality of the EVA itself, the laminating process of the module manufacturer also has a great impact. For example, the bonding degree of EVA is not up to the standard, and the bonding strength between EVA and toughened glass and backplane is not enough, It will cause premature aging of EVA and affect the service life of components.

(3) Battery chip: It is mainly used to generate electricity. The mainstream in the main power generation market are crystalline silicon solar cells and thin film solar cells, both of which have advantages and disadvantages.

The equipment cost of crystalline silicon solar cell is relatively low, but the consumption and cell cost are high, but the photoelectric conversion efficiency is also high, so it is suitable to generate electricity in outdoor sunlight.

Thin film solar cells have high equipment cost, but low consumption and battery cost. However, their photoelectric conversion efficiency is more than half of that of crystalline silicon cells, but their weak light effect is very good. They can also generate electricity under ordinary light, such as solar cells on calculators.

(4) Backboard: function, sealing, insulation and waterproof. Generally, TPT, TPE and other materials must be aging resistant. Most component manufacturers have a 25 year warranty. Tempered glass and aluminum alloy are generally OK. The key is whether the backplane and silica gel can meet the requirements.

(5) Aluminum alloy: protect the laminated parts and play a certain role in sealing and supporting.

(6) Junction box: It protects the whole power generation system and plays the role of current transfer station. If the module is short circuited, the junction box automatically disconnects the short circuited battery string to prevent burning out the junction box of the whole system. The most important thing is the selection of diodes. Depending on the type of battery chips in the module, the corresponding diodes are different.

(7) Silica gel: sealing function, used to seal the junction between components and aluminum alloy frames, components and junction boxes. Some companies use double-sided tape and foam to replace silica gel. Silica gel is widely used in China, with simple process, convenience, easy operation and low cost.